Transcriptomic profiling of IDR CART cells in the CD19 cancer model.

Chimeric antigen receptor (CAR)T cell based therapies demonstrated remarkable efficacies for treating otherwise intractable cancers, particularly B cell malignancies. However, existing FDA-approved CARTs were limited by low antigen sensitivity, rendering their insufficient targeting to low antigen expressing cancers. To improve the antigen sensitivity of CARTs, we engineered CARs targeting CD19, CD22, and HER2 by including intrinsically disordered regions (IDRs) that promote signaling condensation. The CARs fused with IDR from FUS, EWS, or TAF15 triggered enhanced membrane proximal signaling in the CART synapse, which led to an increased release of cytotoxic factors, a higher killing activity towards low antigen-expressing cancer cells in vitro. Moreover, the IDR CARTs induced improved anti tumor effects in vivo in both blood cancer and solid tumor models. No elevated tonic signaling was observed in IDR CARTs. Together, we demonstrated IDRs as a new tool set to enhance CART cytotoxicity and to broaden CART's application to low antigen-expressing cancers.